Trunk Recorder is able to record the calls on trunked and conventional radio systems. It uses 1 or more Software Defined Radios (SDRs) to do this. The SDRs capture large swathes of RF and then use software to process what was received. GNURadio is used to do this processing because it provides lots of convenient RF blocks that can be pieced together to allow for complex RF processing. The libraries from the amazing OP25 project are used for a lot of the P25 functionality. Multiple radio systems can be recorded at the same time.

Trunk Recorder currently supports the following:

• Trunked P25 & SmartNet Systems
• Conventional P25 & analog systems, where each group has a dedicated RF channel
• P25 Phase 1, P25 Phase 2 & Analog voice channels

SDRs supported

• RTL-SDR dongles
• HackRF
• Ettus USRP B200, B210, B205
• BladeRF
• Airspy